Ionization energy is the minimum energy required to remove an electron from an atom. It is usually expressed in units of kJ/mol, that is, the energy in kilojoules required to remove one mole of electrons from one mole of atoms, (a) Calculate the ionization energy for the hydrogen atom, (b) Repeat the calculation, assuming in this second case that the electrons are removed from the n = 2 state instead of from the ground state.